Proving Work is Same for All Paths of a Conservative Force

In summary, the conversation discusses the concept of a conservative force, which is one that only depends on position and has the same work for all paths. The force of gravity is an example of a conservative force, but the participants question whether it can be defined as the gradient of a potential. They also discuss the properties of gravity, such as its direction and magnitude, and how it relates to being a conservative force.
  • #1
Dustinsfl
2,281
5
So for a force to be conservative it can only depend on position and the work as to be the same for all paths.

The force mass time gravity is conservative but how do I show the all paths are the same?
 
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  • #2
Dustinsfl said:
So for a force to be conservative it can only depend on position and the work as to be the same for all paths.

The force mass time gravity is conservative but how do I show the all paths are the same?

Why don't you just show the force can be defined as the gradient of a potential? Guess the potential if you have to.
 
  • #3
Since gravity is acting along the radius to the center of earth, then would ##\mathbf{F}(\mathbf{r}) = -m\mathbf{r}##?
 
  • #4
Dustinsfl said:
Since gravity is acting along the radius to the center of earth, then would ##\mathbf{F}(\mathbf{r}) = -m\mathbf{r}##?

That is a conservative force, but I don't think Newton would agree it has much to do with gravity. What are you thinking?
 
  • #5
Dick said:
That is a conservative force, but I don't think Newton would agree it has much to do with gravity. What are you thinking?

I wrote why I put that.

I said since gravity is acting along the raidus vector to the center of Earth then could I wrtie F in such a manner.
 
  • #6
Dustinsfl said:
I wrote why I put that.

I said since gravity is acting along the raidus vector to the center of Earth then could I wrtie F in such a manner.

There are a LOT of possible forces that would act along a radius vector to the center of the earth. Gravity is a special one. Not that it even matters for showing it's conservative, but don't you know more about gravity than that? -mr increases in magnitude as you move away from the earth. That's not gravity.
 
Last edited:

1. What is the definition of a conservative force?

A conservative force is a type of force that does work on an object that is independent of the path taken by the object. This means that the work done by the force is the same regardless of the path taken, as long as the starting and ending points are the same.

2. Why is it important to prove that work is the same for all paths of a conservative force?

It is important to prove that work is the same for all paths of a conservative force because it helps us understand and predict the behavior of objects under the influence of these forces. It also allows us to simplify calculations and make more accurate predictions in various fields of science and engineering.

3. How can we mathematically prove that work is the same for all paths of a conservative force?

We can use the fundamental theorem of calculus, which states that the integral of a function between two points is equal to the difference of the function evaluated at those points. In this case, we can use this theorem to show that the work done by a conservative force is equal to the difference in potential energy between the starting and ending points, which is independent of the path taken.

4. What are some examples of conservative forces in nature?

Some common examples of conservative forces include gravity, electric forces, and magnetic forces. These forces all follow the principle of work being independent of the path taken and have corresponding potential energy functions.

5. Can a non-conservative force also have the same work for all paths?

No, a non-conservative force does not have the same work for all paths. This is because non-conservative forces, such as friction or air resistance, depend on the path taken by the object and dissipate energy as heat. Therefore, the work done by these forces is not independent of the path taken.

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